The present invention is directed to writing instruments and, in particular, to writing instruments having a retraction mechanism for selectively retracting or extending a writing element.
Writing instruments are commonly equipped with a retractable writing element. According to one example, a writing instrument may include a press button adapted to control the position of the writing element with respect to the writing instrument barrel. When the press button is pressed toward the writing end of the writing instrument, the writing end of the writing element is forced out of the barrel to allow the writing instrument to be used for writing. After the user is finished writing, the press button may be released, or pressed again, to cause the writing end of the writing element to retract back into the barrel.
Due to increasing attention to ergonomic designs, the location, operation, appearance, and structure of writing element retraction mechanisms have varied over the years. For example, International Publication No. WO 94/05512 describes a writing instrument including a barrel for housing a replaceable cartridge, and a retracting plunger mechanism attached to the rear end of the barrel. The retracting plunger is adapted for axial movement between a first position corresponding to the cartridge being retracted within the barrel, and a second position corresponding to the cartridge being protracted from the barrel. A coiled compression spring urges the cartridge and consequently the retracting plunger toward the retracted position. The retracting plunger includes a latch means for engaging a slot in the barrel and locking the retracting plunger in the protracted position. The retaining plunger also includes a projection for maintaining the cartridge in a deflected position that is spaced from the axial centerline of the barrel, such that the compression spring, through the cartridge, imparts a moment on the retracting plunger that transmits a downward force to the latch means. The downward force on the latch means maintains the latch means in the slot in the barrel when in the protracted position. A user may lift up on the latch means to release the latch means from the slot to return the cartridge to the retracted position.
Another example is shown in German Patent Application No. 39 22 777 C1, which discloses a pen having a retractable tip. The pen includes a shaft having a vent hole, and a writing element that may be moved sideways with respect to the longitudinal axis of the shaft. Moving the tip sideways biases the tip onto a sealing surface and maintains the writing element in a retracted position.
Various other retraction mechanism are described in U.S. Pat. No. 6,095,706, United Kingdom Patent Application No. 2 047 629 A, and German Patent No. 37 05 097 A1.
There still remains, however, a need for a writing element retraction mechanism that provides smooth and easy operation, has a reduced number of components, and is aesthetically pleasing and fun to use.
The present invention is directed to a writing instrument. The writing instrument includes a barrel having a channel with an open end, and a writing element disposed in the channel. The writing element is movable between a retracted position and an extended position. At least a portion of the writing element is resilient and may be resiliently deflected in a direction substantially transverse to the longitudinal axis of the writing instrument. The resilient deflection of the writing element biases the writing element to engage the channel and retain the writing element in the extended position. For example, the writing element may be bent such that the resiliency biases the writing element to engage the channel.
According to one embodiment, the writing instrument may include a first engagement member (e.g., a pawl) associated with the writing element, wherein the first engagement member engages the channel. Additionally or alternatively, the writing instrument may include a second engagement member (e.g., an indentation in the barrel), wherein the first engagement member engages the second engagement member. According to another embodiment, the writing instrument may include a sleeve member disposed in the channel for receiving a portion of the writing element. If the sleeve member is provided, the first engagement member may be located on the sleeve member.
According to another aspect of the present invention, movement of the writing element in a direction substantially transverse to the longitudinal axis of the writing instrument disengages the writing element from the channel, such that the writing element returns to the retracted position. This may be accomplished, for example, by bending the writing element.
The writing instrument may further include a release member located on a side surface of the barrel and movable from a rest position to a release position. Movement of the release member to the release position may cause the writing element to disengage from the channel. For example, the release member may bend the writing element. The release member may contact the first engagement member (if provided), or it may contact the writing element at a location spaced from the first engagement member. According to one embodiment, the release member may be a cantilever beam. According to another embodiment, the release member may be pivotably connected to the barrel. According to yet another embodiment, the release member may be a part of a grip element located on the barrel.
According to another aspect of the present invention, the writing instrument may include an actuator member disposed on a side surface of the barrel and movable between a retracted position and an extended position. The actuator member may move along a non-linear path between the retracted and extended positions. For example, the actuator member may move along an arcuate path between the retracted position and the extended position. Further, the actuator member may slide along a non-planar surface between the retracted position and the extended position. The non-planar surface may be concave or any other non-planar surface known in the art.